An inflatable vehicle occupant restraint, such as an air bag, is inflated to protect an occupant of a vehicle upon the occurrence of a vehicle collision. When the vehicle experiences a collision-indicating condition of at least a predetermined threshold level, an inflator is actuated. The inflator then emits inflation fluid which is directed to flow into the air bag. The inflation fluid inflates the air bag from an uninflated condition to an inflated condition in which the air bag extends into the vehicle occupant compartment. When the air bag is inflated into the vehicle occupant compartment, it restrains an occupant of the vehicle from forcefully striking parts of the vehicle as a result of the collision.
An air bag and an inflator are typically assembled together as parts of an air bag module. In addition to the air bag and the inflator, the module includes a reaction canister. The reaction canister contains the air bag and the inflator, and has mounting tabs or other suitable parts for mounting of the module in the vehicle. The reaction canister further has a deployment opening through which the air bag emerges from the reaction canister when the air bag is being inflated.
The air bag has an inlet opening for receiving inflation fluid from the inflator. A retainer ring extends around the inlet opening. The retainer ring is fastened to the air bag, and is fastened to the reaction canister to anchor the air bag in the reaction canister. A deployment door extends over the deployment opening in the reaction canister to conceal the air bag and the other parts of the module from the vehicle occupant compartment.
When the inflator is actuated, the reaction canister directs the inflation fluid to flow from the inflator to the inlet opening in the air bag. As the inflation fluid enters the air bag, it begins to move the air bag outward through the deployment opening in the reaction canister. The inflation fluid then moves the air bag forcefully against the deployment door. The deployment door is ruptured by the force of the fluid pressure in the air bag, and is moved out of the path of the air bag as the inflation fluid continues to inflate the air bag outward from the reaction canister through the deployment opening and into the vehicle occupant compartment.